CN104907558A - A rare earth permanent magnetic material preparing method - Google Patents
A rare earth permanent magnetic material preparing method Download PDFInfo
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- CN104907558A CN104907558A CN201510366476.1A CN201510366476A CN104907558A CN 104907558 A CN104907558 A CN 104907558A CN 201510366476 A CN201510366476 A CN 201510366476A CN 104907558 A CN104907558 A CN 104907558A
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Abstract
The invention relates to a rare earth permanent magnetic material preparing method comprising the steps of preparing a press blank of powder of sintered magnets, using row wires to machine the press blank and then performing sintering. All the steps are performed in a wholly sealed atmosphere. The row wire machining means line machining for the press blank formed by pressing; after the press blank is clamped and located, a driving mechanism drives the row wires to move back and forth linearly; the press blank is machined according to a preset path along with the rotation of a locating clamp and finally forms a block body or a sheet body with a preset shape and size, an arched body or other specially-shaped bodies; the final forming size contains the sintering shrinkage allowance. The rare earth permanent magnetic material preparing method has the advantages of short preparation technological process, high machining efficiency, low magnetic powder loss, and high rare earth utilization rate. The machining is near net machining, so that a finish machining procedure performed after sintering is saved.
Description
Technical field
The present invention relates to a kind of method manufacturing rare earth permanent-magnetic material, belong to sintered magnet preparing technical field, particularly relate to sintered Nd-Fe-B permanent magnetic material preparation technology.
Background technology
Rare-earth sintering magnet is a kind of rare earth permanent-magnetic material manufactured by powder metallurgical technique principle, because of the feature such as its high remanent magnetism, high-coercive force, high energy product, volume be little, lightweight, product, except being applied to the fields such as electroacoustic component, Medical Devices, sensor, magnetic separation, magnetic, is widely used in comprising in all types of industries motor in the fields such as automobile, computer hard disc, wind-power electricity generation, electric tool, electric bicycle, compressor of air conditioner, elevator, Aero-Space especially.
High-performance Ne-Fe-B material requires very high to production line and preparation method, and especially for NdFeB material prepared by sintering process, granularity of magnet powder is thinner, and material is more oxidizable, and the improper meeting of preparation technology causes magnetic property deterioration even to be scrapped.In prior art, rare-earth sintering magnet normally manufactures by the following method: pulverize magnetic rare earth alloy and become alloy powder, compacting alloy powder acquisition pressing blank, sinter pressing blank and carry out Ageing Treatment, machined to sintered body.Usually to transfer after powder process and pressed compact packaging closures or transport, with avoid NdFeB material before the forming with shaping after touch outside air produce problem of oxidation, but this packaging closures mode needs manual operation usually, and air-tightness is difficult to ensure, produce high trade mark magnetic material by this way very difficult, and cannot mass automatic production be adapted to.
At present, have a small amount of producer pilot production anaerobic forming and sintering device, such as CN202336578U, weighing case, passage, totally-enclosed press, sintering are all connected and sealed by it, and with nitrogen protection, but this device carries out cutting processing to pressed compact before relating to sintering.
In addition, after sintering, the usual density of magnet is large and harder, and it is very crisp, add the machined load that man-hour requirement is very large, after sintering, the cutting processing of magnet is bothersome, consuming time with grinding, increases production cost, the waste production time, and sintering after the recycling of processing clout more difficult, cause rare earth material utilization rate low.
Although some producers and research and development institution's pilot production are cut with moving blade with being impregnated in artificial oil by pressing blank; but artificial oil needs to remove after dicing with before sintering; as removed not exclusively; magnetic property serious deterioration will be made; cause that sintering time is long, energy consumption is high; and be unfavorable for obtaining high energy product neodymium iron boron magnetic body, more cannot be applicable to the large-scale production of high energy product neodymium iron boron magnetic body.
During current sintered magnet is produced, still cannot solve the problem such as the oxidation of Magnaglo pressed compact work in-process, processing bits adhesion, fusion, burning, need to add antioxidant in powder process and die mould, need in process to apply cooling agent, cutting liquid, lubricant or anti-fusion powder, and these, the extra step removing these additives or powder need be increased on the one hand, on the other hand once remove the deterioration that not exclusively can bring magnetic property.
Summary of the invention
In order to solve the problem, the preferred embodiment for the present invention provides the method for the manufacture sintered magnet that a kind of rare earth loss is low, production efficiency is high.
Further, the method can solve the problem of the oxidation of Magnaglo pressed compact work in-process, the adhesion of processing bits, fusion, burning, the method can not add any antioxidant in powder process and die mould, can not apply any cooling agent, cutting liquid, lubricant or anti-fusion powder in process.
Further, the processing clout of pressing blank can directly be recycled, the large-scale production of high, the especially applicable high energy product neodymium iron boron magnetic body of rare earth material utilization rate.
Object of the present invention carrys out specific implementation by the following technical programs:
A kind of rare earth permanent-magnetic material production method, comprises the following steps: prepare the pressing blank of sintered magnet powder, utilize winding displacement to process pressing blank, sinter afterwards, and institute all performs in steps in Integral sealing atmosphere.
Preferably, powder step is clearly set after the process, the powder on pressing blank is removed.
Preferably, described powder process is that melted magnetic alloy is sent into fuel pulverizing plant, obtains the Magnaglo of required particle diameter after corase grind, hydrogen embrittlement, airflow milling; Preferably, the particle diameter of this Magnaglo is 2-5 μm.
In preferred detailed description of the invention, by the first conveying mechanism, magnetic alloy is sent into fuel pulverizing plant, described fuel pulverizing plant comprises kibbling mill, hydrogen embrittlement stove, the airflow milling of airtight connection.
Preferably, compressingly obtain pressing blank, be will be obtained magnetic powder particles orientation die mould, be then pressed into pressing blank through isostatic cool pressing.
Preferably, described compressing in do not need particular manufacturing craft, the such as particular manufacturing craft of shaping arc magnet, flaky magnet, magnet ring, only adopt universal mold compacting.
Preferably, described pressing blank density is 4-4.5g/cm
3.
In preferred embodiment, Magnaglo is carried to weighing case by airtight second conveyor structure, shaping at directional magnetic field machine after weighing, then isostatic pressing machine is compressing, obtain pressing blank, described weighing case, directional magnetic field moulding press and the airtight connection of isostatic compaction press.
Preferably, above-mentioned powder process or die mould step do not need to add any antioxidant.
Described winding displacement processing carries out stripping processing to compressing pressing blank, and pressing blank is cut into multiple part.Be specially, while winding displacement and pressing blank relative motion, pressing blank cut.
One of preferred embodiment is, pressing blank is clamped and locates, winding displacement is driven to carry out linear reciprocating motion by drive unit, along with the motion of workpiece positioning clamp, according to the path preset, pressing blank is processed, this processing is carried out with specific speed of related movement, final molding be predetermined shape and size block, lamellar body, arc or other is special-shaped, this final molding size is reserved with sintering shrinkage surplus; Preferably, described processing by CAD/CAM software Computer Aided Design, and by optimizing sintering stock layout layout, calculates required sintering shrinkage surplus.
In preferred embodiment, sent in winding displacement processing unit (plant) by the pressing blank suppressed by the 3rd airtight conveying mechanism, this processing unit (plant) comprises winding displacement, driving mechanism, oxygen content mechanism for monitoring and Control for Oxygen Content mechanism; Preferably, line tension and winding displacement spacing adjusting mechanism, workpiece positioning clamp is also comprised; Preferably, positioning fixture can rotate; More preferably, positioning fixture can be 360 ° of rotating localization jigs.
Preferably, also arrange the first surplus material recovery device, described first surplus material recovery device collects powder falling, blanking, tailing in process, recycling after reclaiming; More preferably, described first clout gathering-device comprises guide inclined-plane and collects chassis, or the first clout gathering-device comprises the broach hopper powder collection device of band push-pull valve.
Preferably, described winding displacement is set to many, and arrange with predetermined spacing between each bar line, this spacing depends on the size of the block after processing or lamellar body, and each bar winding displacement is arranged on the crossbeam of winding displacement installing rack; More preferably, line tension and distance between centers of tracks guiding mechanism are also arranged on installing rack, adjust the line tension of winding displacement and distance between centers of tracks, adapt to the processing needs of pressing blank different densities, different size.
Preferably, drive winding displacement reciprocating along a certain predetermined direction by drive motors, such as Z-direction is reciprocating.
Further, the reciprocating motion speed of winding displacement is line feed speed, if winding displacement is exactly line feed speed along the speed that Z-direction is reciprocating; The reciprocating frequency of winding displacement is 50-100 time/min, preferred 60-80 time/min.Winding displacement is process velocity relative to the translational speed of pressing blank, and preferred process velocity is less than 30mm/min, preferably more than 20mm/min; More preferably no more than 15mm/min or be no more than 10mm/min.
Add man-hour, line is applied some tension in advance, namely processes load, and this tension force is preferably 10-30N, is more preferably 20-30N; According to shape and the size needs of machine-shaping, and consider working (machining) efficiency, described line process velocity can adopt constant speed or speed change.
One of inventive point of the present invention is, adopts the line feed speed of change.Preferably, in a reciprocating stroke of winding displacement, in forward stroke, speed is by 0 being increased to maximum, being down to 0 by maximum again; In backstroke, speed is by 0 being increased to maximum, being down to 0 by maximum again.Preferably, the mode of speed lifting can be linear, also can be that curvilinear motion is as sine wave change.Research shows, preferably, and max line feed speed V
maxfollowing relational expression is met with pressing blank thickness D:
V
max≤K1×D+K2；
Wherein: V
maxfor the max line feed speed of winding displacement, unit is mm/min;
D is pressing blank thickness, and unit is mm;
K1 is a correction factor, and value is 0.1-1;
K2 is a constant, and value is 0-15.
Winding displacement can use the line not having abrasive grains to adhere to, but preferably uses the line with abrasive grains.The core of described winding displacement is steel wire, steel fibre, carbide alloy silk, carbide alloy fiber or nylon fiber, preferred employing stainless steel wire, abrasive grains is fixed on core, preferably adopts plating or electro-deposition to be coated on heart yearn by abrasive grains, ensures chip resistance good in process; In preferred detailed description of the invention, the diameter of line/fiber used is 0.05-2mm, preferred 0.2-0.5mm, abrasive grains selects high hardness material, preferred diamond, carborundum, silicon nitride, aluminium nitride, aluminium oxide etc., abrasive grains average grain diameter is 10-500 μm, preferred 100-200 μm.
The present inventor finds, when the oxygen concentration of processing closed atmosphere is at below 100ppm, under specific line process velocity, there will not be Powder Oxidation and burning in process, also there will not be fusion between processing block.
Further, research shows: in the processing of described winding displacement closed atmosphere oxygen content with do not sinter the relation of magnetic resistance to oxidation time and meet following table:
The above-mentioned resistance to oxidation time all obtains under any antioxidant is not added in powder process and die mould.
Further, the present inventor also finds, consider magnet deformation rate after sintering, the allowance of winding displacement is formulated by following relational expression, namely expects the following relational expression of thickness d demand fulfillment of block/lamellar body 2. after the allowance m of winding displacement and pressing blank density p, machine-shaping:
m＝L1×d-L2×ρ+L3
Wherein: m is winding displacement allowance, unit is μm;
ρ is pressing blank density, and unit is g/cm
3;
D is the thickness of expecting block/lamellar body after machine-shaping, and unit is mm;
L1 is a correction factor, and value is 2-8;
L2 is a correction factor, and value is 15-25;
L3 is a constant, and value is 91.
Preferably, positioning fixture clamping position pressing blank to be processed is utilized in processing; In preferred detailed description of the invention, comprise and rotate grain-clamping table and X, Y and clamp direction adjustment organization and drive motors, by driving motor supplies power, drive described rotation grain-clamping table to be rotated, and then realize in process, driving pressing blank to be rotated; Described X, Y clamp the displacement of grip slipper in X, Y-direction of the adjustable described rotation grain-clamping table of direction adjustment organization, adapt to the clamping position of different size pressing blank thus.Preferably, rotating grain-clamping table is 360 ° of rotation grain-clamping tables.
Oxygen concentration in winding displacement processing unit (plant) place closed system described in described oxygen content monitoring device Real-Time Monitoring and nitrogen pressure, guarantee that oxygen concentration and nitrogen pressure are in set scope.
Preferably, the stroke of winding displacement, reciprocating frequency, machining path and line feed speed, the action of described 360 ° of rotating localization jigs and the oxygen content, nitrogen pressure etc. of Monitoring and Controlling closed atmosphere is controlled by controlling organization.
In preferred detailed description of the invention, add man-hour, first pressing blank is loaded and be positioned positioning fixture, motor drives winding displacement to carry out linear reciprocating motion along a certain predetermined direction, along with the motion of described positioning fixture, process pressing blank according to the path preset, this processing is different from traditional Linear cut, it is that the speed meeting particular requirement is cut pressing blank, thus obtain predetermined shape and size block, lamellar body, arc or other is special-shaped.Under described specific line feed speed, even if do not add any cooling agent, cutting liquid, lubricant or anti-fusion powder in this process, in process, also there will not be Powder Oxidation and burning, between processing block, also there will not be fusion.Preferably, positioning fixture is 360 ° of rotating localization jigs.
Further preferably, preparation method of the present invention also comprises the step that the block/lamellar body after to cutting carries out powder clearly.
In preferred detailed description of the invention, material block after being processed by winding displacement by the 4th conveying mechanism and block/lamellar body are sent in automatic clear powder device, described clear powder device automatically comprises the cylinder of opposite direction rotating, cylinder arranges hairbrush, the burr, chip, micro mist etc. of after winding displacement is processed, expecting the upper and lower surface of block is cleared up by hairbrush, according to production capacity needs, the cylinder that many groups rotate relatively can be set; Preferably, described automatically clear powder device also comprises the second clout gathering-device, and chip, powder that described second clout gathering-device is cleared up hairbrush are collected, reclaimed.
Concrete, by the 5th conveying mechanism, the material block after clear powder is sent in sintering equipment.Preferably, described sintering equipment comprises sintering furnace, bin and elevating mechanism are set in sintering furnace, described elevating mechanism accepts the material block of the powder clearly placed in the charging tray from the 4th conveying mechanism, then send in the charging tray of bin in sintering furnace by material block, sintering furnace is undertaken sintering and heat treatment by predetermined technique after cutting out, and opens fire door after cooling, material block shifts out by elevating mechanism in sintering furnace, obtains sintered magnet product.
Owing to not adding any cooling agent, cutting liquid, lubricant or anti-fusion powder in process, without the need to removing these additives or adding powder in sintering, thus sintering temperature is compared to the low 30-40 DEG C of sintering temperature of traditional R-T-B permanent-magnet material, and temperature retention time is short compared with the conventional sintering time; Sintering temperature of the present invention is 1000 DEG C to 1050 DEG C, carries out under inertia or vacuum condition, insulation 1-1.5 hour, and sintering energy consumption is low; Namely the sintered magnet close to net shape and size is obtained after sintering.Under allowance calculates accurate situation, do not need to carry out fine finishining after sintering and can obtain qualified sintered magnet.
Preferably, described clout recycling step also carries out in closed atmosphere, specifically comprise described first clout gathering-device, described second clout gathering-device, 6th transport establishment, also comprise demagnetizer and secondary fuel pulverizing plant, the powder falling in winding displacement processing unit (plant) in process collected by described first clout gathering-device, blanking, tailing, the chip that in described clear powder device, hairbrush is cleared up collected by described second clout gathering-device, powder, after the powder of two surplus material recovery devices collects, send into described demagnetizer through the 6th conveying mechanism to demagnetize, send into fuel pulverizing plant again.Certainly, also first can demagnetize respectively, then send into fuel pulverizing plant respectively.
Preferably, above-mentioned each device unlatching, run all controlling organization control under carry out.Preferably, controlling organization comprises each Setup Controller, interactive correspondence device and master control machine, described each Setup Controller carries out communication, control, feedback by interactive correspondence device and master control machine, and controls the operation of each several part device of this closed system and the oxygen concentration of closed system and nitrogen pressure.
Especially it is to be noted, winding displacement adds man-hour to pressing blank, because the wire diameter of winding displacement is smaller, preferred 0.05-2mm, line feed speed slowly, be less than 30mm/min, preferably more than 25mm/min, more preferably no more than 15mm/min, or be no more than 10mm/min, and this line is applied in some tension (namely processing load), predetermined tension is 10-30N, be more preferably 20-30N, the mode that the cutting processing of winding displacement to pressing blank is actually to peel off micro powder granule makes the magnetic-particle of formation pressing blank be separated with pressing blank, the heat produced in process is very little, and control the oxygen concentration of closed atmosphere at below 100ppm, ensure that Magnaglo can not produce burning, oxidation, powder bonding and fusion problem, thus in powder process and die mould, any antioxidant is not added, process does not apply any cooling agent, cutting liquid, lubricant, or anti-fusion powder, and processing clout can directly be recycled, meanwhile, low owing to sintering front pressing blank density, 4-4.5g/cm
3, material is soft, although above-mentioned line feed speed is comparatively slow, process time is short, and removes additive owing to eliminating, add powder and sinter rear accurately machined operation, so preparation technology's flow process is short, working (machining) efficiency is high, the production that is applicable to large-scale sintered magnet, carry out linear cutter compared to conventional art to magnet after sintering, although feed speed is than very fast, usual 100-5000mm/min, after sintering, magnet density is comparatively large, close to 7.5g/cm
3, and material is hard, the processing load that line is applied in is comparatively large, but process time is longer, working (machining) efficiency low, be not suitable for the production of large-scale sintered magnet.
The present invention has following beneficial effect:
1. the present invention carries out stripping processing to pressing blank before sintering, because pressing blank density is low, material is soft, although line feed speed of the present invention is slow, but remove additive owing to eliminating, add powder and the rear accurately machined operation of sintering, its preparation technology's flow process is short, working (machining) efficiency is high, magnetic loss is low, rare earth utilization rate is high, and this processing belongs to nearly clean processing, can save finishing step after sintering; In addition, due to this processing can directly precise forming predetermined shape and size block, lamellar body, arc or other is special-shaped, adapt to miniaturized, complicated, precise treatment at present and produce the needs of magnet, universal mold is adopted during die mould, without the need to using particular manufacturing craft, save Design of Dies and manufacturing cost.
2. the present invention does not add any antioxidant in powder process and die mould, process can not apply any cooling agent, cutting liquid, lubricant or anti-fusion powder, by controlling the oxygen content of atmosphere and the feed speed of winding displacement in winding displacement process, make the resistance to oxidation time sintering front magnetic more than 20 hours, guarantee that Magnaglo pressed compact work in-process is not oxidized, process bits adhesion, fusion, burning.
3. winding displacement processing of the present invention is that the mode of peeling off makes the magnetic-particle of formation pressing blank be separated with pressing blank, by the Proper Match of reciprocating frequency, line feed speed, line tension and wire diameter, the heat produced in its processing is very little, add the oxygen concentration of controlled working closed atmosphere at below 100ppm, ensure that Magnaglo work in-process can not produce oxidation and burning, also there will not be powder to fuse problem.
4. the present invention proposes the line feed speed of change and the relation of pressing blank thickness first, the line feed speed meeting this relational expression can ensure good chip removal ability, high working (machining) efficiency, and extremely low processing caloric value, under guaranteeing this line feed speed, magnetic there will not be oxidation and combustion problem.
5. the present invention also propose line allowance and pressing blank density first, process after expect the relational expression of the thickness of block/lamellar body, meet the allowance of this relational expression, the requirement of sintering magnetic materials deformation rate can be met, guarantee high stock utilization, and the low rare earth proportion of goods damageds, the rare earth proportion of goods damageds making the present invention final are reduced to 1.7%.
6. preparation method of the present invention realizes the direct recycling of processing clout, blanking, improves magnetic material utilization rate, reduces rare earth material loss, saved production cost.
7. preparation method of the present invention can not need to perform the step removing antioxidant, cooling agent, cutting liquid, lubricant in sintering, and compared to traditional sintering process, sintering temperature of the present invention is low, sintering time shortens, and reduces sintering energy consumption.
8. preparation method's entirety of the present invention is carried out in closed atmosphere, oxygen concentration controls in micro-oxygen scope, namely oxygen concentration is at below 100ppm, the oxygen uptake that material is possible is in process of production reduced to greatest extent, greatly reduce the oxygen content of final magnet product, improve the magnetic energy product of magnet, adapt to the need of production of mass, high trade mark magnet.
Accompanying drawing explanation
Fig. 1 is the rare earth agglomeration permanent magnetic material automation preparation method flow process of the preferred embodiment for the present invention.
Fig. 2 is the rare earth agglomeration permanent magnetic material automatic production line of the preferred embodiment for the present invention.
Fig. 3 is the winding displacement processing unit (plant) schematic diagram of a kind of preferred embodiment of the present invention.
Fig. 4 is the automatically clear powder device of the preferred embodiment for the present invention.
In figure: 401 is material block; 402 is hairbrush cylinder; 403 is conveyer belt.
Fig. 5 is the winding displacement process schematic diagram of the preferred embodiment for the present invention.
Wherein: predefined paths processing pressing blank pressed by 5a-line; Material block schematic diagram after the processing of 5b-winding displacement; Section SEM microstructure schematic diagram after the processing of 5c-winding displacement.
In figure: 501 is line/wire saw; 401 is material block.
Detailed description of the invention
Below the preferred embodiments of the present invention are described, should be appreciated that preferred embodiment described herein is only for instruction and explanation of the present invention, is not intended to limit the present invention.
The rare earth permanent-magnetic material that the specific embodiment of the invention adopts is R-T-B, R is the element that at least one is selected from rare earth element and Y, and T is the transition metal comprising Fe, and B is boron.
Preferably, this alloy comprises Nd and/or Pr of 26-31wt%, Cu, B 0.9-1.1wt% of Al, 0-0.2wt% of Nb, 0-0.2wt% of Co, 0-0.5wt% of Dy, 0-1wt% of 0-5wt%, surplus is Fe.
Following preparation method is adopted to prepare R-T-B rare earth permanent-magnetic material.
As shown in Figure 1-2, first, prepared the slab of R-T-B rare earth permanent-magnetic material by known rapid solidification, specifically comprise: by required composition proportion molten alloy, keep liquation at 1300-1350 DEG C, obtained the slab of thickness 0.01-0.3mm subsequently by single roller rapid quenching.
By the first conveying mechanism, slab is sent into airtight fuel pulverizing plant, first roughly grind, recycling hydrogen crushing furnace carries out fragmentation to slab, and after airflow milling, then obtain the Magnaglo that average grain diameter is 2-5 μm, the average grain diameter of preferred Magnaglo is 2-3 μm; In powder process, the oxygen concentration of closed atmosphere controls at below 500ppm, preferred below 200ppm, more preferably below 100ppm, does not add any antioxidant in powder process.
By airtight second conveyor structure, obtained Magnaglo is sent into compression molding device, first orientation die mould under directional magnetic field, then be pressed into pressing blank through isostatic cool pressing, by secondary pressing process, the pressing blank density of acquisition is 4-4.5g/cm
3, preferred 4.3g/cm
3; Described secondary pressing process is briquetting process well known in the prior art, difference is, does not need here to use particular manufacturing craft, the such as particular manufacturing craft of shaping arc magnet, flaky magnet, magnet ring, only adopt universal mold compacting, and also do not add any antioxidant in compacting.
Then, by the 3rd airtight conveying mechanism, pressing blank is sent in winding displacement processing unit (plant), be block, the lamellar body of predetermined shape and size by pressing blank Precision Machining, arc or other is special-shaped; Particularly, first CAD/CAM software Computer Aided Design is adopted, by sintering stock layout layout and sintering process parameter, in conjunction with sintering magnetic materials performance, sintering shrinkage amount needed for estimation, according to the allowance of thickness d determination winding displacement of expecting block/lamellar body after pressing blank density p, machine-shaping.
This winding displacement processing unit (plant) specifically comprises winding displacement, driving mechanism, oxygen content mechanism for monitoring, controlling organization, line tension and winding displacement spacing adjusting mechanism and workpiece positioning clamp; Preferably, described positioning fixture can rotate; More preferably, positioning fixture can be 360 ° of rotating localization jigs.
In this winding displacement processing unit (plant), the first surplus material recovery device is also set, described first surplus material recovery device collects powder falling, blanking, tailing in process, recycling after reclaiming, described first clout gathering-device comprises guide inclined-plane and collects chassis, or the first clout gathering-device comprises the broach hopper powder collection device of band push-pull valve.
Described winding displacement is set to many, and arrange with predetermined spacing between each bar line, this spacing depends on the size of the block after processing or lamellar body, and each bar winding displacement is arranged on the crossbeam of installing rack; More preferably, line tension and distance between centers of tracks guiding mechanism are also arranged on installing rack, adjust the line tension of winding displacement and distance between centers of tracks, adapt to the processing needs of pressing blank different densities, different size; Drive winding displacement reciprocating along a certain predetermined direction by drive motors, such as Z-direction is reciprocating.
Research shows: the requirement that can meet sintering magnetic materials deformation rate when expecting the following relational expression of the thickness d demand fulfillment of block/lamellar body after the allowance m of winding displacement and pressing blank density p, machine-shaping:
m＝L1×d-L2×ρ+L3
Wherein: m is winding displacement allowance, unit is μm;
ρ is pressing blank density, and unit is g/cm
3;
D is the thickness of expecting block/lamellar body after machine-shaping, and unit is mm;
L1 is a correction factor, and value is 2-8;
L2 is a correction factor, and value is 15-25;
L3 is a constant, and value is 91.
Particularly, be 4g/cm for green density
3, processing after thickness be the magnetic sheet of 5mm, formulate its allowance and be about 36 μm; Be 4.3g/cm for green density
3, processing after thickness be the magnetic sheet of 3mm, formulate its allowance and be about 20 μm; Be 4.5g/cm for green density
3, processing after thickness be the magnetic sheet of 8mm, formulate its allowance and be about 30 μm.
Further research shows: in described winding displacement process, the oxygen content of closed atmosphere meets following table with the relation of sintering front magnetic resistance to oxidation time:
The above-mentioned resistance to oxidation time all tests under any antioxidant is not added in powder process and die mould, and as seen along with atmosphere oxygen content is increased to more than 100ppm from 10ppm, before sintering, the oxidation resistance of magnetic is that geometric progression is successively decreased.
Based on above-mentioned research conclusion, control the oxygen content of the closed system at described winding displacement processing unit (plant) place at below 100ppm, particularly at below 50ppm, and pass into nitrogen, nitrogen pressure controls at 100-500Pa, is specifically preferably 200-300Pa.
Add man-hour, in advance pressing blank to be processed clamped and locate, winding displacement is driven to carry out linear reciprocating motion by drive unit, controlling organization controls the action of the stroke of winding displacement, reciprocating frequency, machining path and line feed speed, described 360 ° of rotating localization jigs, and the oxygen content of Monitoring and Controlling closed atmosphere, nitrogen pressure are in above-mentioned setting range.
Inventor is drawn by lot of experiments research: by the Proper Match of reciprocating frequency, line feed speed, processing load and wire diameter in line processing, add the oxygen concentration of controlled working closed atmosphere in above-mentioned scope, make Magnaglo work in-process can not produce oxidation and burning, also there will not be powder to fuse problem.
Particularly, the reciprocating frequency that described winding displacement is large is 60-80 time/min, line feed speed is no more than 25mm/min, more preferably no more than 10mm/min, and to add man-hour line be 20-30N by the tension force applied in advance, and adopting the stainless steel core wire of 0.2-0.5mm, abrasive grains selects average grain diameter to be the carborundum of 100-200 μm; According to shape and the size needs of machine-shaping, described line feeding is constant speed or speed change.
Preferably, research shows: max line feed speed V
maxgood chip removal ability, high working (machining) efficiency can be ensured when meeting following relational expression with pressing blank thickness D, and extremely low processing caloric value:
V
max≤K1×D+K2
Wherein: V unit is mm/min;
D unit is mm;
K1 is a correction factor, and value is 0.1-1;
K2 is a constant, and value is 0-15.
Particularly, be the pressing blank of 8mm for thickness, its line feed speed is 0.8-23mm/min, determines that this line feed speed is 15mm/min in the present embodiment.
Along with the rotation of positioning fixture, according to the path preset, pressing blank is processed, block, lamellar body that final molding is predetermined shape and size, arc or other is special-shaped (as shown in Fig. 5 a, Fig. 5 b), and this winding displacement process does not apply any cooling agent, cutting liquid, lubricant and/or anti-fusion powder.
Adopt the rear section microstructure of scanning electron microscope sem research winding displacement processing, as shown in Figure 5 c, the microstructure of the similar fracture of dissociating of the section after processing, crystal grain keeps more complete, substantially dissociate along crystal boundary, without obvious line of cut, this and traditional wire cutting are expected that the crystal grain that the section of block occurs usually is imperfect, have the microstructure of obvious line of cut and are had remarkable difference, show that winding displacement of the present invention processing is different from traditional linear cutter, but force the magnetic-particle of pressing blank to be separated along machined surface in the mode peeled off, peel off.
Multiple lamellar bodies/material the block processed sends into the 4th airtight transport establishment, enters automatic powder cleaning device, as shown in Figure 4, is cleared up by hairbrush cylinder to the upper and lower surface of multiple material block simultaneously.
Material block after cleaning is admitted to sintering furnace and sinters, the sintered magnet close to net shape and size is obtained after sintering, wherein sintering process is as follows: sintering temperature is 1000 DEG C to 1050 DEG C, concrete control sintering temperature is 1030 DEG C to 1040 DEG C, carry out under nitrogen or vacuum condition, insulation 1-1.5 hour, without the need to removing the step of cooling agent, cutting liquid, lubricant in sintering; Namely the sintered magnet close to net shape and size is obtained, without the need to follow-up finishing step after sintering.
In addition, technique of the present invention also comprises clout recycling step, collects blanking, tailing in above-mentioned line process, and clears up the chip, the powder that get off in automatic clear powder, demagnetize after collection, carry out powder process again, due to these two collection step be sintering before Magnaglo, thus through demagnetization after, can directly return milling step to recycle, raw material availability is very high thus, and the rare earth proportion of goods damageds are very low, are less than 1.7%.
Preferably, described line feed speed and pressing blank thickness, the diameter of line, the particle diameter of abrasive grains and process closed atmosphere and all have relation.
Fig. 3 provides the winding displacement processing unit (plant) schematic diagram of a kind of preferred embodiment of the present invention.Winding displacement is tensioned and is arranged on coil holder 100, and straight line movement driving mechanism drives coil holder to pump.Particularly, drive driving wheel 151 to rotate by driving shaft 150, one end of flexible chain parts 152 is articulated and connected on described driving wheel 151, and dangling with straight reciprocating motion parts and coil holder 100 after described flexible chain parts 152 are led by guiding parts 153 is connected.During work, driving wheel rotarily drives flexible chain parts circle swing, realizes the rectilinear motion of driven member after the guide effect of guiding parts.When described driven member is in ramp-up cycle, apply lifting force by described driving wheel by flexible chain, when described driven member is in decline cycle, described driven member is smooth descent under the brake force and the Action of Gravity Field of self of driving shaft.
Further, be the smooth motion of driven member, described coil holder 100 is slidably mounted on guide pillar 102; Described guide pillar 102 is preferably vertical direction and installs; And it is preferred further, described flexible chain parts 152 are parallel with described guide pillar 102 with the stroke between described driven member at described guiding parts 153, make the stroke directions of the described flexible chain parts 152 of described guiding parts 153 bottom identical with the stroke directions of described coil holder 100, make described driven member not bear shearing action in stroke.Preferably, guide pillar can arrange at least one according to the size of driven member, according to steady guiding need arrange one or more.
Preferably, rectilinear motion for coil holder 100 does not have deviation more accurate, and guide pillar and framework can adopt multiple fit system, as being slidably matched, built-in ball roll coordinate, wherein said being slidably matched can adopt the coordinating, as guide rail and groove fit of crowning and groove surface; Mating surface can adopt various ways, as face of cylinder cooperation, rectangular channel cooperation or dove-tail cooperation etc.
Described pendency connection refers to, described flexible chain parts bear the part or all of gravity of described driven member, so just makes described driven member jointly be realized by brake force and Action of Gravity Field in the process fallen, realizes seamlessly transitting.
Further, the circle swing that described guiding parts guides described flexible chain parts is output into straight reciprocating motion, described guiding parts is preferably directive wheel, described directive wheel is set to two, and subtend is installed, when described flexible chain parts between described directive wheel by time, the directive wheel of both sides carries out spacing to described flexible chain parts, ensure that described flexible chain parts export along single direction straight line, and can not deflection be produced.
One skilled in the art will appreciate that guiding parts is not limited to the directive wheel of two subtends settings, can for the various structures play the guiding role.Such as, can for having the fixed guide block of vertical gathering sill, circular arc process is carried out according to the direction of motion of flexible chain parts in preferred gathering sill top, avoids causing impact when leading to flexible chain parts; For another example, guiding parts also can be the fixed guide block with hollow channel, flexible chain parts dangle with driven member be connected through hollow channel, its other ends, preferred hollow channel top is according to the smoothing process of the direction of motion of flexible chain parts, as being treated to the level and smooth chamfering upwards expanded outwardly, to avoid causing impact when leading to flexible chain parts.
Preferably, described flexible chain parts is partly or entirely flexible structure.Described flexible chain parts are flexible structure by the part of described guiding parts, and the flexible chain parts of other parts can be flexible structure, also can be rigid structure.
Described flexible structure is rope; Preferred further, described rope is steel wire rope, nylon rope or other cordage; Preferred further, described rope can be composite construction, namely adopt the mixed sth. made by twisting of multiple material (such as adopting steel wire, nylon and polyester fiber to carry out mixed sth. made by twisting) or adopt layer structure, adopt layer structure to refer to and comprise sandwich layer and top layer, sandwich layer adopts stretch-proof material, and top layer adopts high-abrasive material.
Preferred further, same driving shaft can arrange multiple driving wheel.Like this, during drive shaft turns, multiple driving wheel drives respective flexible chain parts to carry out linear actuation motion respectively.The work initial phase of the flexible chain parts on multiple driving wheel can be identical, multiple driven member can be had like this to be driven and move up and down simultaneously; The work initial phase of the flexible chain parts on multiple driving wheel can be different, and during work, multiple driven member is driven but moves up and down inconsistent; Preferably, the work initial phase of the flexible chain parts on multiple driving wheel is different and phase difference is equal.
The preferred embodiment of the present invention is as Fig. 3, and described driving wheel is set to two, the initialization phase of the flexible chain parts on two driving wheels 180 degree.
Described driving wheel, in the process implemented, also can be set to three or four by those skilled in the art, when described driving wheel is set to three, and the operating phase difference 120 degree of the flexible chain parts on three driving wheels; When described driving wheel is set to four, the operating phase difference 90 degree of the flexible chain parts on four driving wheels.
Preferably, described driving shaft is driven by decelerator by motor.
Those skilled in the art are it is easily understood that under the prerequisite of not conflicting, and above-mentioned each preferred version freely can combine, superpose.
Technology contents of the present invention and technical characteristic have disclosed as above; but those of ordinary skill in the art still may do all replacement and the modification that do not deviate from spirit of the present invention based on teaching of the present invention and announcement; therefore; scope should be not limited to the content that embodiment discloses; and various do not deviate from replacement of the present invention and modification should be comprised, and contained by the claims in the present invention.
Claims (10)
1. a rare earth permanent-magnetic material preparation method, is characterized in that: comprise the following steps: prepare the pressing blank of sintered magnet powder, utilize winding displacement to process pressing blank, sinter afterwards, and institute all performs in steps in an Integral sealing atmosphere; Preferably, before pressing blank, also have milling step, described milling step also carries out in described Integral sealing atmosphere; Preferably, after winding displacement processing, also arrange powder step clearly, described clear powder step is also carried out in described Integral sealing atmosphere; Preferably, in winding displacement processing and/or clear powder step, also arrange clout recycling step, return milling step recycling after reclaimed materials demagnetization, described clout recycling step also carries out in described Integral sealing atmosphere; Preferably, described pressing blank comprises magnetic field orientating compacting and isostatic cool pressing compacting; Preferably, winding displacement processing carries out line processing to compressing pressing blank, pressing blank is clamped and locates, winding displacement is driven to carry out linear reciprocating motion by driving mechanism, along with the rotation of positioning fixture, according to the path preset, pressing blank is processed, final molding be predetermined shape and size block, lamellar body, arc or other is special-shaped, this final molding size is reserved with sintering shrinkage surplus; Preferably, described winding displacement is set to many, arranges and comes on the installing rack of upper and lower end, this installing rack is provided with line tension and distance between centers of tracks guiding mechanism between each line with predetermined spacing.
2. preparation method according to claim 1, winding displacement allowance and the pressing blank density of described winding displacement, process after expect that the thickness of block/lamellar body meets following relational expression:
m＝L1×d－L2×ρ+L3
Wherein: m is winding displacement allowance, unit is μm;
ρ is pressing blank density, and unit is g/cm
3;
D is the thickness of expecting block/lamellar body after machine-shaping, and unit is mm;
L1 is a correction factor, and value is 2-8;
L2 is a correction factor, and value is 15-25;
L3 is a constant, and value is 91.
3. preparation method according to claim 1 and 2, is characterized in that: described winding displacement adopts the line feed speed of change; Preferably, in a reciprocating stroke of winding displacement, in forward stroke, speed is by 0 being increased to maximum, being down to O by maximum again; In backstroke, speed is by 0 being increased to maximum, being down to O by maximum again; Preferably, the mode of speed eustasy can be linear, also can be that curvilinear motion is as sine wave change; Preferably, max line feed speed V
maxfollowing relational expression is met with pressing blank thickness D:
V
max≤K1×D+K2
Wherein: V unit is mm/min;
D unit is mm;
K1 is a correction factor, and value is 0.1-1;
K2 is a constant, and value is 0-15.
4. preparation method according to claim 3, is characterized in that: the reciprocating frequency of described winding displacement is 50-100 time/min, preferred 60-80 time/min; Preferably, the max line feed speed of described winding displacement is less than 30mm/min, preferably more than 20mm/min; More preferably no more than 15mm/min or be no more than 10mm/min; Preferably, described winding displacement is applied some tension in advance, and this tension force is 10-30N, preferred 20-30N; Preferably, the core of described winding displacement is steel wire, steel fibre, carbide alloy silk, carbide alloy fiber or nylon fiber, abrasive grains is fixed on core, the diameter of described line/fiber is 0.05-2mm, abrasive grains is diamond, carborundum, silicon nitride, aluminium nitride, aluminium oxide, and abrasive grains average grain diameter is 10-500 μm; Preferably, the diameter of described line/fiber is 0.2-0.5mm, and abrasive grains average grain diameter is 100-200 μm.
5. the preparation method according to above-mentioned arbitrary claim, is characterized in that: in described winding displacement process, the oxygen content of closed atmosphere meets following table with the relation of sintering front magnetic resistance to oxidation time:
Wherein, the described resistance to oxidation time be powder process and compressing time do not add resistance to oxidation time under any antioxidant.
6. the preparation method according to above-mentioned arbitrary claim, is characterized in that: described milling step is that melted magnetic alloy is sent into fuel pulverizing plant, obtains the Magnaglo of required particle diameter after corase grind, hydrogen embrittlement, airflow milling; Preferably, the particle diameter of described Magnaglo is 2-5 μm.
7. the preparation method according to above-mentioned arbitrary claim, is characterized in that: described clear powder step is the cylinder adopting opposite direction rotating between two, and cylinder arranges hairbrush, is cleared up burr, the chip of expecting the upper and lower surface of block after winding displacement is processed by hairbrush.
8. the preparation method according to above-mentioned arbitrary claim, it is characterized in that: without the need to removing antioxidant, cooling agent, cutting liquid, lubricant or anti-fusion powder in described sintering step, sintering temperature is 1000 DEG C to 1050 DEG C, carry out under inertia or vacuum condition, insulation 1-1.5 hour.
9. the preparation method according to above-mentioned arbitrary claim, is characterized in that: described rare earth permanent-magnetic material is R-Fe-B, R is the element that at least one is selected from rare earth element and Y, and T is the transition metal comprising Fe, and B is boron.
10. the preparation method according to above-mentioned arbitrary claim, is characterized in that: described rare earth permanent-magnetic material comprises: Cu, B 0.9-1.1wt% of Al, 0-0.2wt% of Nb, 0-0.2wt% of Co, 0-0.5wt% of Nd and/or Pr of 26-31wt%, Dy, 0-1wt% of 0-5wt%, surplus are Fe.
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| CN110379614A (en) * | 2019-06-26 | 2019-10-25 | 宁波金轮磁材技术有限公司 | A kind of processing technology of magnetic patch |
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| CN110379614A (en) * | 2019-06-26 | 2019-10-25 | 宁波金轮磁材技术有限公司 | A kind of processing technology of magnetic patch |
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